Floating-wrist-pin construction for internal-combustion engines



Jul 1, 193a. s, EQJ QN 1,769,474

FLOATING WRIST PIN CONSTRUCTION FOR INTERNAL COMBUSTION ENGINES jVE/V 51/EN60/V Patented July 1, 1930 I SVEN' SVENSON, BOND DU LAG, WISCOltTSIN.

,F oArINe-wmsT-rm coNsrRucrIoN non INTERNAL-COMBUSTIbNENGINES Application 'fiieese tmter a0, 1929. Serial No. 396,363.

The present invention relates to an improved manner of mounting the, wrist pin in the piston of the cylinder of an internal combustion engine, whereby, although the wrist pin is free to rotate in both the eye of the connecting "rod and its bearings in the piston, it is effectively restrained from movement in the direction of its axis by the provision of simple fastening devices, and

so cannot engage the'walls of the cylinder and score the latter.-'

The wrist pin is of tubular formation, and it is maintained in its relatively fixed longitudinal position in the piston, by means of 16 specially formed sheet steel washers, having a central embossmentdisplaced from the plane of the sheetfo-r engaging the tubular wrist pin interiorly at its ends with a tight fit. The concentric margin of the washers, lying in the plane of the sheet and outside of the embossment, is adapted to abut the ends of the wrist pin and the adj acent'surfaces of the piston surrounding the bore constituting the bearings in which the wrist pin is entered.

The bottom of the embossment of the said washers is perforated for the passagetherethroughof a loop of wire, the loop engaging the washers at both ends of the wrist pin, and being twisted so as to place the wire under tension, and hold the Washers in a definite and fixed position with relation to the wrist pin. a V

By placing the connecting wire under ten sion, vibration of the straight runs of the latter is avoided, and yet allowance is provided for expansion within the elastic limits of the metal of which the washers and the wire are formed.

Having thus outlined the nature of my invention, I will now specifically describe the same, and in the appended claims will point out the novelty residing inthe invention.

In the drawing:

Figure 1 is a vertical central sectional view through a piston, its connecting rod, the floating wrist pin, and the special means employed for securing the wrist pin in a relatively fixed position.

Fig. '2 is a perspective View, looking into the depression of the embossment of one of. the specially formed washers.

In'the drawing, the numeral 10 indicates .a piston of usualconstruct-ion formed with internal aligned bearings 11 and 12 for the ends of the wrist pin, the "latter passing through an eye in the upper end of a connecting rod 13. On opposite sides, and in line with the bore forming the bearings for, I

the wrist pin, the piston is counter-bored asat 15 and 16. In the drawing, the counterbores are exaggerated somewhat as to depth over the boring's of the actual construction.-

A tubular "wrist pin 17, having a length approximately equal to the distance between the seats of the bore through the piston, is passed into the bore and through the eye of the connecting rod 13. Although in the drawing I have shown the'ends of the wrist I pin as counter-bored, this isnot anecessary feature of my construction, inasmuch as the tubular wrist pin may be 'of uniform gauge from end to end, ormay'be provided with -'bore's;t apering from each end, asfusual, without counterbores. The wrist pin'is free to rotaterboth in its bearings in the piston and in the'eye of the connecting rod."

'To'secure the floating wrist pin against longitudinal movement, and so prevent its ends from scoringthe walls ofithecylinder, which sometimes happens when ,undue length-wiseexpansion or movement ofthe wrist pin occurs, I providea very sim le means for securing the'wrist pin in a rel tively fixed-position, and so avoid any tendency to damage the walls o-fthe cylinder. Ineifecting'this result, I stamp from resilient sheet metal steel, special washers 18 of the form shown in Fig; 2, the washers being A,

circular in formation, and provided with a central depression forming an e'mbossrnent 19, in the form of an offset fromthe plane of the sheet. The circular wall of the embossment 19 connecting the concentric flange 20 and the bottom 2l,-is of a-diameterto cause it to fit snugly' in the end of=the wrist pin, it being preferable that the embossments on the washers be sprung into position.

The bottom 21 of the washer is provided with a; plurality of perforations, one-of which is indicated by the numeral 22. It is preferable that the perforations'be equally spaced as shown in Fig. 2, so that when tension is exerted, there will be an equal distribution of resistance throughout the wash- 7 er. l Between two opposite perforations 22, M I form Jinthe bottom of the depression an upstanding transverse rib; 23, of; rounded cross section, as shown in Fig. 1.

10- v i the eyeof tlieconnectingLr'od13 and in the' bearings- 11 "and l2 o f thepiston,' I in} V sert thewashers, as described. The eonce'n-- After the wrist pin has been positioned in trio flanges of thewashers arebrought into close engagement' with the ends of the .;wrist pin, and also-bear lightlyon'theadj aceiit surfacesat the bottom of the counterv .bore: in the piston surrounding the bore for thev hearings; ,I. then 1001), asuitable wire 24 of selected length, and pass the straight "ilitunslof thewire through two 'ofthe holes 22 in-the 'washer,.o ne on each sideof theround- 7 ed rib-23,;so that the loop 'ofthe said wire ting the piston in regions surrounding the ends ofthe hearings therein, and a looped wire passing through perforations in the washers with the endsof the wire twisted to place the wire under tension and fix the washers in the ends of thewrist pin.-

2 A piston having aligned transverse I bearings for a wrist pin, and a connecting rod, a tubular wrist pin disposed in the said bearingsvand the eyelof the connecting rod and in'floating relation both to the bearings and the eye, sheet metal washers provided with depressions orrembossinents with perforations in the bottom of the said depresisionsror embossinents, the walls of the dethe concentric margins of the washers abutpressions or embossments engagedinside the ends of the wrist pin with a tight fit, and the concentric marginsof the washers abutting the piston in regions surrounding the rib' formed on the bottom "of theenibossnents, and a looped wire passing through perforations in thewashers and about-the said transverse ribs, with -the ends of the wire twisted to place the wire under tension ".85 ends. of they bearings therein, a transverse andfix the washersin the ends of thewrist.

pin.

In testinoo n 3 whereof, JIQhave signe d iny 7 name atMilwaukee,thisj Sth day of Augushw ,svEN-svE soN.

herent resiliency and flexibility, both in the re and 'inrthe structure ofthebottom of ersgln the event that the parts become unheated,thejelastieity residing in the e n w lilpen it e pa s n heydepression -prenibossment of the washdesired degree, ,but ,the wrist, pin cannot a move longitudinallyto-any considerable extent. Consequently,anypossible damage to I .t a the walls of the cylinder-1,; on account of1un-"-: ,due longitudinal movement ofthewristpin,

is, avoided. vThe straight runs of thewire are placed under tension in the twistingto- V i l j gether of the ends thereof, so thatvibration p and crystallization of the structure of the Having thus described iny invention, what I claim and desire to seeurejby LettersPat-f entof the" United States, is: a

,bearings for awrist pin, a11d a connecting 1. A piston having aligned transverse rod,; v a' tubularfwrist pin disposed in-the said- 7 bear ngs and the eye of the a connecting rod 7 a di lfiOittihg relation gbot'hltlo the r ngs andfthe eye, sheet metal washers provided 7 with depressions or embossments with perforations in the bottornf'of the 'saiddepresslonsonembossments, the walls gofthe de 'pressions or embossinents engaged inside the nds f theivrist p n wi h' atigh ffi d 

